A screenshot of the immersive world within the app. Photograph: Universal Everything

For PolyFauna, we were approached by Radiohead's Thom Yorke and Stanley Donwood, the band's long-time visual collaborator, after they had seen our Super-Computer-Romantics show at La Gaite Lyrique in Paris, and our website and sleeve work for Warp Records.

They had a very clear but open idea of what they wanted: to go beyond a linear music video and build an app that is an immersive, ever-changing world. The app would be made by exploring the music from studio sessions of Radiohead's last album, King of Limbs, and Stanley's organic pen and ink drawings.

The idea was to create a world to experience Radiohead's music in a totally different way – something beyond a remix or a download that would push the boundaries of what music and digital can do when brought together fully. We hoped the experience of PolyFauna would be unique to each individual person, rather than everybody having the same record or app with the same sounds and images. We also wanted to open up the possibilities of what music can mean in the digital age, beyond tiny thumbnail artwork and YouTube.

The process of development was similar to that of an art school: open and full of collaboration. Thom and Stanley shared our desire to challenge technology and invent a unique and special experience, so we began by sharing our inspirations, such as Karl Sims' Evolving Virtual Creatures video, which sparked the idea to create a living world inside the app.

Over the course of nine months, PolyFauna gradually took shape as we went back and forth between the band's studio in Oxford and ours in Sheffield – we shared drawings, music and prototypes over many creative discussions around non-linear musical structures. It was a real exploration of analogue audio-visual creativity and the opportunities that digital offers to create new experiences.

We've been surprised by the app in a few ways. First, how quickly people were able to figure out how it worked. Many apps and games begin with tutorials, but we intentionally omitted any explanation and kept the instructions to a minimum. This added to the app's sense of discovery, giving the user a feeling of satisfaction that you wouldn't get from just following commands on-screen.

All of the interactions – drawing on the screen, moving your body, following the red dot – have rewarding effects. We expected this discovery phase to take place over a few weeks, but many users were able to fully traverse the app within the first day.

PolyFauna is a standalone work, not tied into any new release, tour or PR event – this allowed us to craft the work and explore different avenues more easily than if there was a fixed point. In our first group meeting, all eight of us involved brought some amazing ideas to the table. The difficult part was to whittle those down into a coherent experience. To other app and game designers, I would stress this editing process before getting too far into production: prototype a few ideas, feel out what works, but be sure to cut the rest.

I have to admit, we were a little nervous about the app going live. Radiohead has a very keen and invested fan base – the kind who look for cryptic clues, hidden messages and conspiracies in their music and art. We were unsure whether they would think we had "ruined" the track, made an obscure piece of art or that they would simply go with us and Radiohead into the world of PolyFauna. Once Thom Yorke had quietly announced it on the band's website, the response was huge – we received over 100,000 downloads in the first hour alone.

App facts

Length of the project: three months full-time, spread out to fit schedulesCompanies involved: Universal Everything, Radiohead, Stanley Donwood, Nigel Godrich Size of the team: full-time, one developer; part-time, creative direction from all parties; sound from three contributorsType of finance: Direct commission